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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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*
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* This file is a part of LEMON, a generic C++ optimization library.
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*
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* Copyright (C) 2003-2011
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* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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* (Egervary Research Group on Combinatorial Optimization, EGRES).
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*
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* Permission to use, modify and distribute this software is granted
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* provided that this copyright notice appears in all copies. For
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* precise terms see the accompanying LICENSE file.
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*
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* This software is provided "AS IS" with no warranty of any kind,
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* express or implied, and with no claim as to its suitability for any
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* purpose.
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*
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*/
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#ifndef LEMON_COST_SCALING_H
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#define LEMON_COST_SCALING_H
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/// \ingroup min_cost_flow_algs
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/// \file
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/// \brief Cost scaling algorithm for finding a minimum cost flow.
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#include <vector>
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#include <deque>
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#include <limits>
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#include <lemon/core.h>
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#include <lemon/maps.h>
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#include <lemon/math.h>
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#include <lemon/static_graph.h>
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#include <lemon/circulation.h>
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#include <lemon/bellman_ford.h>
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namespace lemon {
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/// \brief Default traits class of CostScaling algorithm.
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///
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/// Default traits class of CostScaling algorithm.
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/// \tparam GR Digraph type.
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/// \tparam V The number type used for flow amounts, capacity bounds
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/// and supply values. By default it is \c int.
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/// \tparam C The number type used for costs and potentials.
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/// By default it is the same as \c V.
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#ifdef DOXYGEN
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template <typename GR, typename V = int, typename C = V>
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#else
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template < typename GR, typename V = int, typename C = V,
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bool integer = std::numeric_limits<C>::is_integer >
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#endif
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struct CostScalingDefaultTraits
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{
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/// The type of the digraph
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typedef GR Digraph;
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/// The type of the flow amounts, capacity bounds and supply values
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typedef V Value;
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/// The type of the arc costs
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typedef C Cost;
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/// \brief The large cost type used for internal computations
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///
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/// The large cost type used for internal computations.
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/// It is \c long \c long if the \c Cost type is integer,
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/// otherwise it is \c double.
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/// \c Cost must be convertible to \c LargeCost.
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typedef double LargeCost;
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};
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// Default traits class for integer cost types
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template <typename GR, typename V, typename C>
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struct CostScalingDefaultTraits<GR, V, C, true>
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{
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typedef GR Digraph;
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typedef V Value;
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typedef C Cost;
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#ifdef LEMON_HAVE_LONG_LONG
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typedef long long LargeCost;
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#else
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typedef long LargeCost;
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#endif
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};
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/// \addtogroup min_cost_flow_algs
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/// @{
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/// \brief Implementation of the Cost Scaling algorithm for
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/// finding a \ref min_cost_flow "minimum cost flow".
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///
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/// \ref CostScaling implements a cost scaling algorithm that performs
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/// push/augment and relabel operations for finding a \ref min_cost_flow
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/// "minimum cost flow" \ref amo93networkflows, \ref goldberg90approximation,
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/// \ref goldberg97efficient, \ref bunnagel98efficient.
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/// It is a highly efficient primal-dual solution method, which
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/// can be viewed as the generalization of the \ref Preflow
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/// "preflow push-relabel" algorithm for the maximum flow problem.
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///
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/// Most of the parameters of the problem (except for the digraph)
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/// can be given using separate functions, and the algorithm can be
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/// executed using the \ref run() function. If some parameters are not
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/// specified, then default values will be used.
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///
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/// \tparam GR The digraph type the algorithm runs on.
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/// \tparam V The number type used for flow amounts, capacity bounds
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/// and supply values in the algorithm. By default, it is \c int.
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/// \tparam C The number type used for costs and potentials in the
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/// algorithm. By default, it is the same as \c V.
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/// \tparam TR The traits class that defines various types used by the
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/// algorithm. By default, it is \ref CostScalingDefaultTraits
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/// "CostScalingDefaultTraits<GR, V, C>".
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/// In most cases, this parameter should not be set directly,
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/// consider to use the named template parameters instead.
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///
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/// \warning Both number types must be signed and all input data must
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/// be integer.
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/// \warning This algorithm does not support negative costs for such
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/// arcs that have infinite upper bound.
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///
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/// \note %CostScaling provides three different internal methods,
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/// from which the most efficient one is used by default.
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/// For more information, see \ref Method.
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#ifdef DOXYGEN
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template <typename GR, typename V, typename C, typename TR>
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#else
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template < typename GR, typename V = int, typename C = V,
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typename TR = CostScalingDefaultTraits<GR, V, C> >
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#endif
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class CostScaling
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{
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public:
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/// The type of the digraph
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typedef typename TR::Digraph Digraph;
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/// The type of the flow amounts, capacity bounds and supply values
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typedef typename TR::Value Value;
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/// The type of the arc costs
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typedef typename TR::Cost Cost;
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/// \brief The large cost type
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///
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/// The large cost type used for internal computations.
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/// By default, it is \c long \c long if the \c Cost type is integer,
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/// otherwise it is \c double.
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typedef typename TR::LargeCost LargeCost;
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/// The \ref CostScalingDefaultTraits "traits class" of the algorithm
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typedef TR Traits;
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public:
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/// \brief Problem type constants for the \c run() function.
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///
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/// Enum type containing the problem type constants that can be
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/// returned by the \ref run() function of the algorithm.
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enum ProblemType {
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/// The problem has no feasible solution (flow).
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INFEASIBLE,
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/// The problem has optimal solution (i.e. it is feasible and
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/// bounded), and the algorithm has found optimal flow and node
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/// potentials (primal and dual solutions).
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OPTIMAL,
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/// The digraph contains an arc of negative cost and infinite
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/// upper bound. It means that the objective function is unbounded
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/// on that arc, however, note that it could actually be bounded
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/// over the feasible flows, but this algroithm cannot handle
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/// these cases.
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UNBOUNDED
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};
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/// \brief Constants for selecting the internal method.
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///
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/// Enum type containing constants for selecting the internal method
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/// for the \ref run() function.
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///
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/// \ref CostScaling provides three internal methods that differ mainly
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/// in their base operations, which are used in conjunction with the
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/// relabel operation.
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/// By default, the so called \ref PARTIAL_AUGMENT
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/// "Partial Augment-Relabel" method is used, which proved to be
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/// the most efficient and the most robust on various test inputs.
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/// However, the other methods can be selected using the \ref run()
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/// function with the proper parameter.
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enum Method {
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/// Local push operations are used, i.e. flow is moved only on one
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/// admissible arc at once.
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PUSH,
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/// Augment operations are used, i.e. flow is moved on admissible
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/// paths from a node with excess to a node with deficit.
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AUGMENT,
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/// Partial augment operations are used, i.e. flow is moved on
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/// admissible paths started from a node with excess, but the
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/// lengths of these paths are limited. This method can be viewed
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/// as a combined version of the previous two operations.
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PARTIAL_AUGMENT
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};
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private:
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TEMPLATE_DIGRAPH_TYPEDEFS(GR);
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typedef std::vector<int> IntVector;
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typedef std::vector<Value> ValueVector;
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typedef std::vector<Cost> CostVector;
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typedef std::vector<LargeCost> LargeCostVector;
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typedef std::vector<char> BoolVector;
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// Note: vector<char> is used instead of vector<bool> for efficiency reasons
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private:
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template <typename KT, typename VT>
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class StaticVectorMap {
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public:
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typedef KT Key;
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typedef VT Value;
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StaticVectorMap(std::vector<Value>& v) : _v(v) {}
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const Value& operator[](const Key& key) const {
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return _v[StaticDigraph::id(key)];
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}
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Value& operator[](const Key& key) {
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return _v[StaticDigraph::id(key)];
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}
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void set(const Key& key, const Value& val) {
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_v[StaticDigraph::id(key)] = val;
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}
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private:
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std::vector<Value>& _v;
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};
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typedef StaticVectorMap<StaticDigraph::Node, LargeCost> LargeCostNodeMap;
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typedef StaticVectorMap<StaticDigraph::Arc, LargeCost> LargeCostArcMap;
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private:
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// Data related to the underlying digraph
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const GR &_graph;
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int _node_num;
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int _arc_num;
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int _res_node_num;
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int _res_arc_num;
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int _root;
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// Parameters of the problem
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bool _have_lower;
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Value _sum_supply;
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int _sup_node_num;
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// Data structures for storing the digraph
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IntNodeMap _node_id;
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IntArcMap _arc_idf;
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IntArcMap _arc_idb;
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IntVector _first_out;
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BoolVector _forward;
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IntVector _source;
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IntVector _target;
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IntVector _reverse;
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// Node and arc data
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ValueVector _lower;
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ValueVector _upper;
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CostVector _scost;
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ValueVector _supply;
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ValueVector _res_cap;
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LargeCostVector _cost;
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LargeCostVector _pi;
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ValueVector _excess;
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IntVector _next_out;
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std::deque<int> _active_nodes;
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// Data for scaling
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LargeCost _epsilon;
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int _alpha;
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IntVector _buckets;
|
kpeter@839
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IntVector _bucket_next;
|
kpeter@839
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IntVector _bucket_prev;
|
kpeter@839
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IntVector _rank;
|
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285 |
int _max_rank;
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// Data for a StaticDigraph structure
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typedef std::pair<int, int> IntPair;
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StaticDigraph _sgr;
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std::vector<IntPair> _arc_vec;
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std::vector<LargeCost> _cost_vec;
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LargeCostArcMap _cost_map;
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LargeCostNodeMap _pi_map;
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public:
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/// \brief Constant for infinite upper bounds (capacities).
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///
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/// Constant for infinite upper bounds (capacities).
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/// It is \c std::numeric_limits<Value>::infinity() if available,
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/// \c std::numeric_limits<Value>::max() otherwise.
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const Value INF;
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public:
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/// \name Named Template Parameters
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/// @{
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template <typename T>
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struct SetLargeCostTraits : public Traits {
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typedef T LargeCost;
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};
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/// \brief \ref named-templ-param "Named parameter" for setting
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315 |
/// \c LargeCost type.
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///
|
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/// \ref named-templ-param "Named parameter" for setting \c LargeCost
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318 |
/// type, which is used for internal computations in the algorithm.
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/// \c Cost must be convertible to \c LargeCost.
|
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320 |
template <typename T>
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321 |
struct SetLargeCost
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: public CostScaling<GR, V, C, SetLargeCostTraits<T> > {
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|
323 |
typedef CostScaling<GR, V, C, SetLargeCostTraits<T> > Create;
|
kpeter@809
|
324 |
};
|
kpeter@809
|
325 |
|
kpeter@809
|
326 |
/// @}
|
kpeter@809
|
327 |
|
kpeter@863
|
328 |
protected:
|
kpeter@863
|
329 |
|
kpeter@863
|
330 |
CostScaling() {}
|
kpeter@863
|
331 |
|
kpeter@809
|
332 |
public:
|
kpeter@809
|
333 |
|
kpeter@809
|
334 |
/// \brief Constructor.
|
kpeter@808
|
335 |
///
|
kpeter@809
|
336 |
/// The constructor of the class.
|
kpeter@809
|
337 |
///
|
kpeter@809
|
338 |
/// \param graph The digraph the algorithm runs on.
|
kpeter@809
|
339 |
CostScaling(const GR& graph) :
|
kpeter@809
|
340 |
_graph(graph), _node_id(graph), _arc_idf(graph), _arc_idb(graph),
|
kpeter@809
|
341 |
_cost_map(_cost_vec), _pi_map(_pi),
|
kpeter@809
|
342 |
INF(std::numeric_limits<Value>::has_infinity ?
|
kpeter@809
|
343 |
std::numeric_limits<Value>::infinity() :
|
kpeter@809
|
344 |
std::numeric_limits<Value>::max())
|
kpeter@808
|
345 |
{
|
kpeter@812
|
346 |
// Check the number types
|
kpeter@809
|
347 |
LEMON_ASSERT(std::numeric_limits<Value>::is_signed,
|
kpeter@809
|
348 |
"The flow type of CostScaling must be signed");
|
kpeter@809
|
349 |
LEMON_ASSERT(std::numeric_limits<Cost>::is_signed,
|
kpeter@809
|
350 |
"The cost type of CostScaling must be signed");
|
alpar@877
|
351 |
|
kpeter@830
|
352 |
// Reset data structures
|
kpeter@809
|
353 |
reset();
|
kpeter@808
|
354 |
}
|
kpeter@808
|
355 |
|
kpeter@809
|
356 |
/// \name Parameters
|
kpeter@809
|
357 |
/// The parameters of the algorithm can be specified using these
|
kpeter@809
|
358 |
/// functions.
|
kpeter@809
|
359 |
|
kpeter@809
|
360 |
/// @{
|
kpeter@809
|
361 |
|
kpeter@809
|
362 |
/// \brief Set the lower bounds on the arcs.
|
kpeter@808
|
363 |
///
|
kpeter@809
|
364 |
/// This function sets the lower bounds on the arcs.
|
kpeter@809
|
365 |
/// If it is not used before calling \ref run(), the lower bounds
|
kpeter@809
|
366 |
/// will be set to zero on all arcs.
|
kpeter@808
|
367 |
///
|
kpeter@809
|
368 |
/// \param map An arc map storing the lower bounds.
|
kpeter@809
|
369 |
/// Its \c Value type must be convertible to the \c Value type
|
kpeter@809
|
370 |
/// of the algorithm.
|
kpeter@809
|
371 |
///
|
kpeter@809
|
372 |
/// \return <tt>(*this)</tt>
|
kpeter@809
|
373 |
template <typename LowerMap>
|
kpeter@809
|
374 |
CostScaling& lowerMap(const LowerMap& map) {
|
kpeter@809
|
375 |
_have_lower = true;
|
kpeter@809
|
376 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
377 |
_lower[_arc_idf[a]] = map[a];
|
kpeter@809
|
378 |
_lower[_arc_idb[a]] = map[a];
|
kpeter@808
|
379 |
}
|
kpeter@808
|
380 |
return *this;
|
kpeter@808
|
381 |
}
|
kpeter@808
|
382 |
|
kpeter@809
|
383 |
/// \brief Set the upper bounds (capacities) on the arcs.
|
kpeter@808
|
384 |
///
|
kpeter@809
|
385 |
/// This function sets the upper bounds (capacities) on the arcs.
|
kpeter@809
|
386 |
/// If it is not used before calling \ref run(), the upper bounds
|
kpeter@809
|
387 |
/// will be set to \ref INF on all arcs (i.e. the flow value will be
|
kpeter@812
|
388 |
/// unbounded from above).
|
kpeter@808
|
389 |
///
|
kpeter@809
|
390 |
/// \param map An arc map storing the upper bounds.
|
kpeter@809
|
391 |
/// Its \c Value type must be convertible to the \c Value type
|
kpeter@809
|
392 |
/// of the algorithm.
|
kpeter@809
|
393 |
///
|
kpeter@809
|
394 |
/// \return <tt>(*this)</tt>
|
kpeter@809
|
395 |
template<typename UpperMap>
|
kpeter@809
|
396 |
CostScaling& upperMap(const UpperMap& map) {
|
kpeter@809
|
397 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
398 |
_upper[_arc_idf[a]] = map[a];
|
kpeter@808
|
399 |
}
|
kpeter@808
|
400 |
return *this;
|
kpeter@808
|
401 |
}
|
kpeter@808
|
402 |
|
kpeter@809
|
403 |
/// \brief Set the costs of the arcs.
|
kpeter@809
|
404 |
///
|
kpeter@809
|
405 |
/// This function sets the costs of the arcs.
|
kpeter@809
|
406 |
/// If it is not used before calling \ref run(), the costs
|
kpeter@809
|
407 |
/// will be set to \c 1 on all arcs.
|
kpeter@809
|
408 |
///
|
kpeter@809
|
409 |
/// \param map An arc map storing the costs.
|
kpeter@809
|
410 |
/// Its \c Value type must be convertible to the \c Cost type
|
kpeter@809
|
411 |
/// of the algorithm.
|
kpeter@809
|
412 |
///
|
kpeter@809
|
413 |
/// \return <tt>(*this)</tt>
|
kpeter@809
|
414 |
template<typename CostMap>
|
kpeter@809
|
415 |
CostScaling& costMap(const CostMap& map) {
|
kpeter@809
|
416 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
417 |
_scost[_arc_idf[a]] = map[a];
|
kpeter@809
|
418 |
_scost[_arc_idb[a]] = -map[a];
|
kpeter@809
|
419 |
}
|
kpeter@809
|
420 |
return *this;
|
kpeter@809
|
421 |
}
|
kpeter@809
|
422 |
|
kpeter@809
|
423 |
/// \brief Set the supply values of the nodes.
|
kpeter@809
|
424 |
///
|
kpeter@809
|
425 |
/// This function sets the supply values of the nodes.
|
kpeter@809
|
426 |
/// If neither this function nor \ref stSupply() is used before
|
kpeter@809
|
427 |
/// calling \ref run(), the supply of each node will be set to zero.
|
kpeter@809
|
428 |
///
|
kpeter@809
|
429 |
/// \param map A node map storing the supply values.
|
kpeter@809
|
430 |
/// Its \c Value type must be convertible to the \c Value type
|
kpeter@809
|
431 |
/// of the algorithm.
|
kpeter@809
|
432 |
///
|
kpeter@809
|
433 |
/// \return <tt>(*this)</tt>
|
kpeter@809
|
434 |
template<typename SupplyMap>
|
kpeter@809
|
435 |
CostScaling& supplyMap(const SupplyMap& map) {
|
kpeter@809
|
436 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
kpeter@809
|
437 |
_supply[_node_id[n]] = map[n];
|
kpeter@809
|
438 |
}
|
kpeter@809
|
439 |
return *this;
|
kpeter@809
|
440 |
}
|
kpeter@809
|
441 |
|
kpeter@809
|
442 |
/// \brief Set single source and target nodes and a supply value.
|
kpeter@809
|
443 |
///
|
kpeter@809
|
444 |
/// This function sets a single source node and a single target node
|
kpeter@809
|
445 |
/// and the required flow value.
|
kpeter@809
|
446 |
/// If neither this function nor \ref supplyMap() is used before
|
kpeter@809
|
447 |
/// calling \ref run(), the supply of each node will be set to zero.
|
kpeter@809
|
448 |
///
|
kpeter@809
|
449 |
/// Using this function has the same effect as using \ref supplyMap()
|
kpeter@809
|
450 |
/// with such a map in which \c k is assigned to \c s, \c -k is
|
kpeter@809
|
451 |
/// assigned to \c t and all other nodes have zero supply value.
|
kpeter@809
|
452 |
///
|
kpeter@809
|
453 |
/// \param s The source node.
|
kpeter@809
|
454 |
/// \param t The target node.
|
kpeter@809
|
455 |
/// \param k The required amount of flow from node \c s to node \c t
|
kpeter@809
|
456 |
/// (i.e. the supply of \c s and the demand of \c t).
|
kpeter@809
|
457 |
///
|
kpeter@809
|
458 |
/// \return <tt>(*this)</tt>
|
kpeter@809
|
459 |
CostScaling& stSupply(const Node& s, const Node& t, Value k) {
|
kpeter@809
|
460 |
for (int i = 0; i != _res_node_num; ++i) {
|
kpeter@809
|
461 |
_supply[i] = 0;
|
kpeter@809
|
462 |
}
|
kpeter@809
|
463 |
_supply[_node_id[s]] = k;
|
kpeter@809
|
464 |
_supply[_node_id[t]] = -k;
|
kpeter@809
|
465 |
return *this;
|
kpeter@809
|
466 |
}
|
alpar@877
|
467 |
|
kpeter@809
|
468 |
/// @}
|
kpeter@809
|
469 |
|
kpeter@808
|
470 |
/// \name Execution control
|
kpeter@809
|
471 |
/// The algorithm can be executed using \ref run().
|
kpeter@808
|
472 |
|
kpeter@808
|
473 |
/// @{
|
kpeter@808
|
474 |
|
kpeter@808
|
475 |
/// \brief Run the algorithm.
|
kpeter@808
|
476 |
///
|
kpeter@809
|
477 |
/// This function runs the algorithm.
|
kpeter@809
|
478 |
/// The paramters can be specified using functions \ref lowerMap(),
|
kpeter@809
|
479 |
/// \ref upperMap(), \ref costMap(), \ref supplyMap(), \ref stSupply().
|
kpeter@809
|
480 |
/// For example,
|
kpeter@809
|
481 |
/// \code
|
kpeter@809
|
482 |
/// CostScaling<ListDigraph> cs(graph);
|
kpeter@809
|
483 |
/// cs.lowerMap(lower).upperMap(upper).costMap(cost)
|
kpeter@809
|
484 |
/// .supplyMap(sup).run();
|
kpeter@809
|
485 |
/// \endcode
|
kpeter@809
|
486 |
///
|
kpeter@830
|
487 |
/// This function can be called more than once. All the given parameters
|
kpeter@830
|
488 |
/// are kept for the next call, unless \ref resetParams() or \ref reset()
|
kpeter@830
|
489 |
/// is used, thus only the modified parameters have to be set again.
|
kpeter@830
|
490 |
/// If the underlying digraph was also modified after the construction
|
kpeter@830
|
491 |
/// of the class (or the last \ref reset() call), then the \ref reset()
|
kpeter@830
|
492 |
/// function must be called.
|
kpeter@808
|
493 |
///
|
kpeter@810
|
494 |
/// \param method The internal method that will be used in the
|
kpeter@810
|
495 |
/// algorithm. For more information, see \ref Method.
|
kpeter@810
|
496 |
/// \param factor The cost scaling factor. It must be larger than one.
|
kpeter@808
|
497 |
///
|
kpeter@809
|
498 |
/// \return \c INFEASIBLE if no feasible flow exists,
|
kpeter@809
|
499 |
/// \n \c OPTIMAL if the problem has optimal solution
|
kpeter@809
|
500 |
/// (i.e. it is feasible and bounded), and the algorithm has found
|
kpeter@809
|
501 |
/// optimal flow and node potentials (primal and dual solutions),
|
kpeter@809
|
502 |
/// \n \c UNBOUNDED if the digraph contains an arc of negative cost
|
kpeter@809
|
503 |
/// and infinite upper bound. It means that the objective function
|
kpeter@812
|
504 |
/// is unbounded on that arc, however, note that it could actually be
|
kpeter@809
|
505 |
/// bounded over the feasible flows, but this algroithm cannot handle
|
kpeter@809
|
506 |
/// these cases.
|
kpeter@809
|
507 |
///
|
kpeter@810
|
508 |
/// \see ProblemType, Method
|
kpeter@830
|
509 |
/// \see resetParams(), reset()
|
kpeter@810
|
510 |
ProblemType run(Method method = PARTIAL_AUGMENT, int factor = 8) {
|
kpeter@810
|
511 |
_alpha = factor;
|
kpeter@809
|
512 |
ProblemType pt = init();
|
kpeter@809
|
513 |
if (pt != OPTIMAL) return pt;
|
kpeter@810
|
514 |
start(method);
|
kpeter@809
|
515 |
return OPTIMAL;
|
kpeter@809
|
516 |
}
|
kpeter@809
|
517 |
|
kpeter@809
|
518 |
/// \brief Reset all the parameters that have been given before.
|
kpeter@809
|
519 |
///
|
kpeter@809
|
520 |
/// This function resets all the paramaters that have been given
|
kpeter@809
|
521 |
/// before using functions \ref lowerMap(), \ref upperMap(),
|
kpeter@809
|
522 |
/// \ref costMap(), \ref supplyMap(), \ref stSupply().
|
kpeter@809
|
523 |
///
|
kpeter@830
|
524 |
/// It is useful for multiple \ref run() calls. Basically, all the given
|
kpeter@830
|
525 |
/// parameters are kept for the next \ref run() call, unless
|
kpeter@830
|
526 |
/// \ref resetParams() or \ref reset() is used.
|
kpeter@830
|
527 |
/// If the underlying digraph was also modified after the construction
|
kpeter@830
|
528 |
/// of the class or the last \ref reset() call, then the \ref reset()
|
kpeter@830
|
529 |
/// function must be used, otherwise \ref resetParams() is sufficient.
|
kpeter@809
|
530 |
///
|
kpeter@809
|
531 |
/// For example,
|
kpeter@809
|
532 |
/// \code
|
kpeter@809
|
533 |
/// CostScaling<ListDigraph> cs(graph);
|
kpeter@809
|
534 |
///
|
kpeter@809
|
535 |
/// // First run
|
kpeter@809
|
536 |
/// cs.lowerMap(lower).upperMap(upper).costMap(cost)
|
kpeter@809
|
537 |
/// .supplyMap(sup).run();
|
kpeter@809
|
538 |
///
|
kpeter@830
|
539 |
/// // Run again with modified cost map (resetParams() is not called,
|
kpeter@809
|
540 |
/// // so only the cost map have to be set again)
|
kpeter@809
|
541 |
/// cost[e] += 100;
|
kpeter@809
|
542 |
/// cs.costMap(cost).run();
|
kpeter@809
|
543 |
///
|
kpeter@830
|
544 |
/// // Run again from scratch using resetParams()
|
kpeter@809
|
545 |
/// // (the lower bounds will be set to zero on all arcs)
|
kpeter@830
|
546 |
/// cs.resetParams();
|
kpeter@809
|
547 |
/// cs.upperMap(capacity).costMap(cost)
|
kpeter@809
|
548 |
/// .supplyMap(sup).run();
|
kpeter@809
|
549 |
/// \endcode
|
kpeter@809
|
550 |
///
|
kpeter@809
|
551 |
/// \return <tt>(*this)</tt>
|
kpeter@830
|
552 |
///
|
kpeter@830
|
553 |
/// \see reset(), run()
|
kpeter@830
|
554 |
CostScaling& resetParams() {
|
kpeter@809
|
555 |
for (int i = 0; i != _res_node_num; ++i) {
|
kpeter@809
|
556 |
_supply[i] = 0;
|
kpeter@808
|
557 |
}
|
kpeter@809
|
558 |
int limit = _first_out[_root];
|
kpeter@809
|
559 |
for (int j = 0; j != limit; ++j) {
|
kpeter@809
|
560 |
_lower[j] = 0;
|
kpeter@809
|
561 |
_upper[j] = INF;
|
kpeter@809
|
562 |
_scost[j] = _forward[j] ? 1 : -1;
|
kpeter@809
|
563 |
}
|
kpeter@809
|
564 |
for (int j = limit; j != _res_arc_num; ++j) {
|
kpeter@809
|
565 |
_lower[j] = 0;
|
kpeter@809
|
566 |
_upper[j] = INF;
|
kpeter@809
|
567 |
_scost[j] = 0;
|
kpeter@809
|
568 |
_scost[_reverse[j]] = 0;
|
alpar@877
|
569 |
}
|
kpeter@809
|
570 |
_have_lower = false;
|
kpeter@809
|
571 |
return *this;
|
kpeter@808
|
572 |
}
|
kpeter@808
|
573 |
|
kpeter@830
|
574 |
/// \brief Reset all the parameters that have been given before.
|
kpeter@830
|
575 |
///
|
kpeter@830
|
576 |
/// This function resets all the paramaters that have been given
|
kpeter@830
|
577 |
/// before using functions \ref lowerMap(), \ref upperMap(),
|
kpeter@830
|
578 |
/// \ref costMap(), \ref supplyMap(), \ref stSupply().
|
kpeter@830
|
579 |
///
|
kpeter@830
|
580 |
/// It is useful for multiple run() calls. If this function is not
|
kpeter@830
|
581 |
/// used, all the parameters given before are kept for the next
|
kpeter@830
|
582 |
/// \ref run() call.
|
kpeter@830
|
583 |
/// However, the underlying digraph must not be modified after this
|
kpeter@830
|
584 |
/// class have been constructed, since it copies and extends the graph.
|
kpeter@830
|
585 |
/// \return <tt>(*this)</tt>
|
kpeter@830
|
586 |
CostScaling& reset() {
|
kpeter@830
|
587 |
// Resize vectors
|
kpeter@830
|
588 |
_node_num = countNodes(_graph);
|
kpeter@830
|
589 |
_arc_num = countArcs(_graph);
|
kpeter@830
|
590 |
_res_node_num = _node_num + 1;
|
kpeter@830
|
591 |
_res_arc_num = 2 * (_arc_num + _node_num);
|
kpeter@830
|
592 |
_root = _node_num;
|
kpeter@830
|
593 |
|
kpeter@830
|
594 |
_first_out.resize(_res_node_num + 1);
|
kpeter@830
|
595 |
_forward.resize(_res_arc_num);
|
kpeter@830
|
596 |
_source.resize(_res_arc_num);
|
kpeter@830
|
597 |
_target.resize(_res_arc_num);
|
kpeter@830
|
598 |
_reverse.resize(_res_arc_num);
|
kpeter@830
|
599 |
|
kpeter@830
|
600 |
_lower.resize(_res_arc_num);
|
kpeter@830
|
601 |
_upper.resize(_res_arc_num);
|
kpeter@830
|
602 |
_scost.resize(_res_arc_num);
|
kpeter@830
|
603 |
_supply.resize(_res_node_num);
|
alpar@877
|
604 |
|
kpeter@830
|
605 |
_res_cap.resize(_res_arc_num);
|
kpeter@830
|
606 |
_cost.resize(_res_arc_num);
|
kpeter@830
|
607 |
_pi.resize(_res_node_num);
|
kpeter@830
|
608 |
_excess.resize(_res_node_num);
|
kpeter@830
|
609 |
_next_out.resize(_res_node_num);
|
kpeter@830
|
610 |
|
kpeter@830
|
611 |
_arc_vec.reserve(_res_arc_num);
|
kpeter@830
|
612 |
_cost_vec.reserve(_res_arc_num);
|
kpeter@830
|
613 |
|
kpeter@830
|
614 |
// Copy the graph
|
kpeter@830
|
615 |
int i = 0, j = 0, k = 2 * _arc_num + _node_num;
|
kpeter@830
|
616 |
for (NodeIt n(_graph); n != INVALID; ++n, ++i) {
|
kpeter@830
|
617 |
_node_id[n] = i;
|
kpeter@830
|
618 |
}
|
kpeter@830
|
619 |
i = 0;
|
kpeter@830
|
620 |
for (NodeIt n(_graph); n != INVALID; ++n, ++i) {
|
kpeter@830
|
621 |
_first_out[i] = j;
|
kpeter@830
|
622 |
for (OutArcIt a(_graph, n); a != INVALID; ++a, ++j) {
|
kpeter@830
|
623 |
_arc_idf[a] = j;
|
kpeter@830
|
624 |
_forward[j] = true;
|
kpeter@830
|
625 |
_source[j] = i;
|
kpeter@830
|
626 |
_target[j] = _node_id[_graph.runningNode(a)];
|
kpeter@830
|
627 |
}
|
kpeter@830
|
628 |
for (InArcIt a(_graph, n); a != INVALID; ++a, ++j) {
|
kpeter@830
|
629 |
_arc_idb[a] = j;
|
kpeter@830
|
630 |
_forward[j] = false;
|
kpeter@830
|
631 |
_source[j] = i;
|
kpeter@830
|
632 |
_target[j] = _node_id[_graph.runningNode(a)];
|
kpeter@830
|
633 |
}
|
kpeter@830
|
634 |
_forward[j] = false;
|
kpeter@830
|
635 |
_source[j] = i;
|
kpeter@830
|
636 |
_target[j] = _root;
|
kpeter@830
|
637 |
_reverse[j] = k;
|
kpeter@830
|
638 |
_forward[k] = true;
|
kpeter@830
|
639 |
_source[k] = _root;
|
kpeter@830
|
640 |
_target[k] = i;
|
kpeter@830
|
641 |
_reverse[k] = j;
|
kpeter@830
|
642 |
++j; ++k;
|
kpeter@830
|
643 |
}
|
kpeter@830
|
644 |
_first_out[i] = j;
|
kpeter@830
|
645 |
_first_out[_res_node_num] = k;
|
kpeter@830
|
646 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@830
|
647 |
int fi = _arc_idf[a];
|
kpeter@830
|
648 |
int bi = _arc_idb[a];
|
kpeter@830
|
649 |
_reverse[fi] = bi;
|
kpeter@830
|
650 |
_reverse[bi] = fi;
|
kpeter@830
|
651 |
}
|
alpar@877
|
652 |
|
kpeter@830
|
653 |
// Reset parameters
|
kpeter@830
|
654 |
resetParams();
|
kpeter@830
|
655 |
return *this;
|
kpeter@830
|
656 |
}
|
kpeter@830
|
657 |
|
kpeter@808
|
658 |
/// @}
|
kpeter@808
|
659 |
|
kpeter@808
|
660 |
/// \name Query Functions
|
kpeter@809
|
661 |
/// The results of the algorithm can be obtained using these
|
kpeter@808
|
662 |
/// functions.\n
|
kpeter@809
|
663 |
/// The \ref run() function must be called before using them.
|
kpeter@808
|
664 |
|
kpeter@808
|
665 |
/// @{
|
kpeter@808
|
666 |
|
kpeter@809
|
667 |
/// \brief Return the total cost of the found flow.
|
kpeter@808
|
668 |
///
|
kpeter@809
|
669 |
/// This function returns the total cost of the found flow.
|
kpeter@809
|
670 |
/// Its complexity is O(e).
|
kpeter@809
|
671 |
///
|
kpeter@809
|
672 |
/// \note The return type of the function can be specified as a
|
kpeter@809
|
673 |
/// template parameter. For example,
|
kpeter@809
|
674 |
/// \code
|
kpeter@809
|
675 |
/// cs.totalCost<double>();
|
kpeter@809
|
676 |
/// \endcode
|
kpeter@809
|
677 |
/// It is useful if the total cost cannot be stored in the \c Cost
|
kpeter@809
|
678 |
/// type of the algorithm, which is the default return type of the
|
kpeter@809
|
679 |
/// function.
|
kpeter@808
|
680 |
///
|
kpeter@808
|
681 |
/// \pre \ref run() must be called before using this function.
|
kpeter@809
|
682 |
template <typename Number>
|
kpeter@809
|
683 |
Number totalCost() const {
|
kpeter@809
|
684 |
Number c = 0;
|
kpeter@809
|
685 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
686 |
int i = _arc_idb[a];
|
kpeter@809
|
687 |
c += static_cast<Number>(_res_cap[i]) *
|
kpeter@809
|
688 |
(-static_cast<Number>(_scost[i]));
|
kpeter@809
|
689 |
}
|
kpeter@809
|
690 |
return c;
|
kpeter@808
|
691 |
}
|
kpeter@808
|
692 |
|
kpeter@809
|
693 |
#ifndef DOXYGEN
|
kpeter@809
|
694 |
Cost totalCost() const {
|
kpeter@809
|
695 |
return totalCost<Cost>();
|
kpeter@808
|
696 |
}
|
kpeter@809
|
697 |
#endif
|
kpeter@808
|
698 |
|
kpeter@808
|
699 |
/// \brief Return the flow on the given arc.
|
kpeter@808
|
700 |
///
|
kpeter@809
|
701 |
/// This function returns the flow on the given arc.
|
kpeter@808
|
702 |
///
|
kpeter@808
|
703 |
/// \pre \ref run() must be called before using this function.
|
kpeter@809
|
704 |
Value flow(const Arc& a) const {
|
kpeter@809
|
705 |
return _res_cap[_arc_idb[a]];
|
kpeter@808
|
706 |
}
|
kpeter@808
|
707 |
|
kpeter@809
|
708 |
/// \brief Return the flow map (the primal solution).
|
kpeter@808
|
709 |
///
|
kpeter@809
|
710 |
/// This function copies the flow value on each arc into the given
|
kpeter@809
|
711 |
/// map. The \c Value type of the algorithm must be convertible to
|
kpeter@809
|
712 |
/// the \c Value type of the map.
|
kpeter@808
|
713 |
///
|
kpeter@808
|
714 |
/// \pre \ref run() must be called before using this function.
|
kpeter@809
|
715 |
template <typename FlowMap>
|
kpeter@809
|
716 |
void flowMap(FlowMap &map) const {
|
kpeter@809
|
717 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
718 |
map.set(a, _res_cap[_arc_idb[a]]);
|
kpeter@809
|
719 |
}
|
kpeter@808
|
720 |
}
|
kpeter@808
|
721 |
|
kpeter@809
|
722 |
/// \brief Return the potential (dual value) of the given node.
|
kpeter@808
|
723 |
///
|
kpeter@809
|
724 |
/// This function returns the potential (dual value) of the
|
kpeter@809
|
725 |
/// given node.
|
kpeter@808
|
726 |
///
|
kpeter@808
|
727 |
/// \pre \ref run() must be called before using this function.
|
kpeter@809
|
728 |
Cost potential(const Node& n) const {
|
kpeter@809
|
729 |
return static_cast<Cost>(_pi[_node_id[n]]);
|
kpeter@809
|
730 |
}
|
kpeter@809
|
731 |
|
kpeter@809
|
732 |
/// \brief Return the potential map (the dual solution).
|
kpeter@809
|
733 |
///
|
kpeter@809
|
734 |
/// This function copies the potential (dual value) of each node
|
kpeter@809
|
735 |
/// into the given map.
|
kpeter@809
|
736 |
/// The \c Cost type of the algorithm must be convertible to the
|
kpeter@809
|
737 |
/// \c Value type of the map.
|
kpeter@809
|
738 |
///
|
kpeter@809
|
739 |
/// \pre \ref run() must be called before using this function.
|
kpeter@809
|
740 |
template <typename PotentialMap>
|
kpeter@809
|
741 |
void potentialMap(PotentialMap &map) const {
|
kpeter@809
|
742 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
kpeter@809
|
743 |
map.set(n, static_cast<Cost>(_pi[_node_id[n]]));
|
kpeter@809
|
744 |
}
|
kpeter@808
|
745 |
}
|
kpeter@808
|
746 |
|
kpeter@808
|
747 |
/// @}
|
kpeter@808
|
748 |
|
kpeter@808
|
749 |
private:
|
kpeter@808
|
750 |
|
kpeter@809
|
751 |
// Initialize the algorithm
|
kpeter@809
|
752 |
ProblemType init() {
|
kpeter@821
|
753 |
if (_res_node_num <= 1) return INFEASIBLE;
|
kpeter@809
|
754 |
|
kpeter@809
|
755 |
// Check the sum of supply values
|
kpeter@809
|
756 |
_sum_supply = 0;
|
kpeter@809
|
757 |
for (int i = 0; i != _root; ++i) {
|
kpeter@809
|
758 |
_sum_supply += _supply[i];
|
kpeter@808
|
759 |
}
|
kpeter@809
|
760 |
if (_sum_supply > 0) return INFEASIBLE;
|
alpar@877
|
761 |
|
kpeter@809
|
762 |
|
kpeter@809
|
763 |
// Initialize vectors
|
kpeter@809
|
764 |
for (int i = 0; i != _res_node_num; ++i) {
|
kpeter@809
|
765 |
_pi[i] = 0;
|
kpeter@809
|
766 |
_excess[i] = _supply[i];
|
kpeter@809
|
767 |
}
|
alpar@877
|
768 |
|
kpeter@809
|
769 |
// Remove infinite upper bounds and check negative arcs
|
kpeter@809
|
770 |
const Value MAX = std::numeric_limits<Value>::max();
|
kpeter@809
|
771 |
int last_out;
|
kpeter@809
|
772 |
if (_have_lower) {
|
kpeter@809
|
773 |
for (int i = 0; i != _root; ++i) {
|
kpeter@809
|
774 |
last_out = _first_out[i+1];
|
kpeter@809
|
775 |
for (int j = _first_out[i]; j != last_out; ++j) {
|
kpeter@809
|
776 |
if (_forward[j]) {
|
kpeter@809
|
777 |
Value c = _scost[j] < 0 ? _upper[j] : _lower[j];
|
kpeter@809
|
778 |
if (c >= MAX) return UNBOUNDED;
|
kpeter@809
|
779 |
_excess[i] -= c;
|
kpeter@809
|
780 |
_excess[_target[j]] += c;
|
kpeter@809
|
781 |
}
|
kpeter@809
|
782 |
}
|
kpeter@809
|
783 |
}
|
kpeter@809
|
784 |
} else {
|
kpeter@809
|
785 |
for (int i = 0; i != _root; ++i) {
|
kpeter@809
|
786 |
last_out = _first_out[i+1];
|
kpeter@809
|
787 |
for (int j = _first_out[i]; j != last_out; ++j) {
|
kpeter@809
|
788 |
if (_forward[j] && _scost[j] < 0) {
|
kpeter@809
|
789 |
Value c = _upper[j];
|
kpeter@809
|
790 |
if (c >= MAX) return UNBOUNDED;
|
kpeter@809
|
791 |
_excess[i] -= c;
|
kpeter@809
|
792 |
_excess[_target[j]] += c;
|
kpeter@809
|
793 |
}
|
kpeter@809
|
794 |
}
|
kpeter@809
|
795 |
}
|
kpeter@809
|
796 |
}
|
kpeter@809
|
797 |
Value ex, max_cap = 0;
|
kpeter@809
|
798 |
for (int i = 0; i != _res_node_num; ++i) {
|
kpeter@809
|
799 |
ex = _excess[i];
|
kpeter@809
|
800 |
_excess[i] = 0;
|
kpeter@809
|
801 |
if (ex < 0) max_cap -= ex;
|
kpeter@809
|
802 |
}
|
kpeter@809
|
803 |
for (int j = 0; j != _res_arc_num; ++j) {
|
kpeter@809
|
804 |
if (_upper[j] >= MAX) _upper[j] = max_cap;
|
kpeter@808
|
805 |
}
|
kpeter@808
|
806 |
|
kpeter@809
|
807 |
// Initialize the large cost vector and the epsilon parameter
|
kpeter@809
|
808 |
_epsilon = 0;
|
kpeter@809
|
809 |
LargeCost lc;
|
kpeter@809
|
810 |
for (int i = 0; i != _root; ++i) {
|
kpeter@809
|
811 |
last_out = _first_out[i+1];
|
kpeter@809
|
812 |
for (int j = _first_out[i]; j != last_out; ++j) {
|
kpeter@809
|
813 |
lc = static_cast<LargeCost>(_scost[j]) * _res_node_num * _alpha;
|
kpeter@809
|
814 |
_cost[j] = lc;
|
kpeter@809
|
815 |
if (lc > _epsilon) _epsilon = lc;
|
kpeter@809
|
816 |
}
|
kpeter@809
|
817 |
}
|
kpeter@809
|
818 |
_epsilon /= _alpha;
|
kpeter@808
|
819 |
|
kpeter@809
|
820 |
// Initialize maps for Circulation and remove non-zero lower bounds
|
kpeter@809
|
821 |
ConstMap<Arc, Value> low(0);
|
kpeter@809
|
822 |
typedef typename Digraph::template ArcMap<Value> ValueArcMap;
|
kpeter@809
|
823 |
typedef typename Digraph::template NodeMap<Value> ValueNodeMap;
|
kpeter@809
|
824 |
ValueArcMap cap(_graph), flow(_graph);
|
kpeter@809
|
825 |
ValueNodeMap sup(_graph);
|
kpeter@809
|
826 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
kpeter@809
|
827 |
sup[n] = _supply[_node_id[n]];
|
kpeter@808
|
828 |
}
|
kpeter@809
|
829 |
if (_have_lower) {
|
kpeter@809
|
830 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
831 |
int j = _arc_idf[a];
|
kpeter@809
|
832 |
Value c = _lower[j];
|
kpeter@809
|
833 |
cap[a] = _upper[j] - c;
|
kpeter@809
|
834 |
sup[_graph.source(a)] -= c;
|
kpeter@809
|
835 |
sup[_graph.target(a)] += c;
|
kpeter@809
|
836 |
}
|
kpeter@809
|
837 |
} else {
|
kpeter@809
|
838 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
839 |
cap[a] = _upper[_arc_idf[a]];
|
kpeter@809
|
840 |
}
|
kpeter@809
|
841 |
}
|
kpeter@808
|
842 |
|
kpeter@839
|
843 |
_sup_node_num = 0;
|
kpeter@839
|
844 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
kpeter@839
|
845 |
if (sup[n] > 0) ++_sup_node_num;
|
kpeter@839
|
846 |
}
|
kpeter@839
|
847 |
|
kpeter@808
|
848 |
// Find a feasible flow using Circulation
|
kpeter@809
|
849 |
Circulation<Digraph, ConstMap<Arc, Value>, ValueArcMap, ValueNodeMap>
|
kpeter@809
|
850 |
circ(_graph, low, cap, sup);
|
kpeter@809
|
851 |
if (!circ.flowMap(flow).run()) return INFEASIBLE;
|
kpeter@809
|
852 |
|
kpeter@809
|
853 |
// Set residual capacities and handle GEQ supply type
|
kpeter@809
|
854 |
if (_sum_supply < 0) {
|
kpeter@809
|
855 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
856 |
Value fa = flow[a];
|
kpeter@809
|
857 |
_res_cap[_arc_idf[a]] = cap[a] - fa;
|
kpeter@809
|
858 |
_res_cap[_arc_idb[a]] = fa;
|
kpeter@809
|
859 |
sup[_graph.source(a)] -= fa;
|
kpeter@809
|
860 |
sup[_graph.target(a)] += fa;
|
kpeter@809
|
861 |
}
|
kpeter@809
|
862 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
kpeter@809
|
863 |
_excess[_node_id[n]] = sup[n];
|
kpeter@809
|
864 |
}
|
kpeter@809
|
865 |
for (int a = _first_out[_root]; a != _res_arc_num; ++a) {
|
kpeter@809
|
866 |
int u = _target[a];
|
kpeter@809
|
867 |
int ra = _reverse[a];
|
kpeter@809
|
868 |
_res_cap[a] = -_sum_supply + 1;
|
kpeter@809
|
869 |
_res_cap[ra] = -_excess[u];
|
kpeter@809
|
870 |
_cost[a] = 0;
|
kpeter@809
|
871 |
_cost[ra] = 0;
|
kpeter@809
|
872 |
_excess[u] = 0;
|
kpeter@809
|
873 |
}
|
kpeter@809
|
874 |
} else {
|
kpeter@809
|
875 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
kpeter@809
|
876 |
Value fa = flow[a];
|
kpeter@809
|
877 |
_res_cap[_arc_idf[a]] = cap[a] - fa;
|
kpeter@809
|
878 |
_res_cap[_arc_idb[a]] = fa;
|
kpeter@809
|
879 |
}
|
kpeter@809
|
880 |
for (int a = _first_out[_root]; a != _res_arc_num; ++a) {
|
kpeter@809
|
881 |
int ra = _reverse[a];
|
kpeter@839
|
882 |
_res_cap[a] = 0;
|
kpeter@809
|
883 |
_res_cap[ra] = 0;
|
kpeter@809
|
884 |
_cost[a] = 0;
|
kpeter@809
|
885 |
_cost[ra] = 0;
|
kpeter@809
|
886 |
}
|
kpeter@809
|
887 |
}
|
alpar@877
|
888 |
|
kpeter@809
|
889 |
return OPTIMAL;
|
kpeter@809
|
890 |
}
|
kpeter@809
|
891 |
|
kpeter@809
|
892 |
// Execute the algorithm and transform the results
|
kpeter@810
|
893 |
void start(Method method) {
|
kpeter@810
|
894 |
// Maximum path length for partial augment
|
kpeter@810
|
895 |
const int MAX_PATH_LENGTH = 4;
|
kpeter@839
|
896 |
|
alpar@877
|
897 |
// Initialize data structures for buckets
|
kpeter@839
|
898 |
_max_rank = _alpha * _res_node_num;
|
kpeter@839
|
899 |
_buckets.resize(_max_rank);
|
kpeter@839
|
900 |
_bucket_next.resize(_res_node_num + 1);
|
kpeter@839
|
901 |
_bucket_prev.resize(_res_node_num + 1);
|
kpeter@839
|
902 |
_rank.resize(_res_node_num + 1);
|
alpar@877
|
903 |
|
kpeter@809
|
904 |
// Execute the algorithm
|
kpeter@810
|
905 |
switch (method) {
|
kpeter@810
|
906 |
case PUSH:
|
kpeter@810
|
907 |
startPush();
|
kpeter@810
|
908 |
break;
|
kpeter@810
|
909 |
case AUGMENT:
|
kpeter@909
|
910 |
startAugment(_res_node_num - 1);
|
kpeter@810
|
911 |
break;
|
kpeter@810
|
912 |
case PARTIAL_AUGMENT:
|
kpeter@810
|
913 |
startAugment(MAX_PATH_LENGTH);
|
kpeter@810
|
914 |
break;
|
kpeter@809
|
915 |
}
|
kpeter@809
|
916 |
|
kpeter@809
|
917 |
// Compute node potentials for the original costs
|
kpeter@809
|
918 |
_arc_vec.clear();
|
kpeter@809
|
919 |
_cost_vec.clear();
|
kpeter@809
|
920 |
for (int j = 0; j != _res_arc_num; ++j) {
|
kpeter@809
|
921 |
if (_res_cap[j] > 0) {
|
kpeter@809
|
922 |
_arc_vec.push_back(IntPair(_source[j], _target[j]));
|
kpeter@809
|
923 |
_cost_vec.push_back(_scost[j]);
|
kpeter@809
|
924 |
}
|
kpeter@809
|
925 |
}
|
kpeter@809
|
926 |
_sgr.build(_res_node_num, _arc_vec.begin(), _arc_vec.end());
|
kpeter@809
|
927 |
|
kpeter@809
|
928 |
typename BellmanFord<StaticDigraph, LargeCostArcMap>
|
kpeter@809
|
929 |
::template SetDistMap<LargeCostNodeMap>::Create bf(_sgr, _cost_map);
|
kpeter@809
|
930 |
bf.distMap(_pi_map);
|
kpeter@809
|
931 |
bf.init(0);
|
kpeter@809
|
932 |
bf.start();
|
kpeter@809
|
933 |
|
kpeter@809
|
934 |
// Handle non-zero lower bounds
|
kpeter@809
|
935 |
if (_have_lower) {
|
kpeter@809
|
936 |
int limit = _first_out[_root];
|
kpeter@809
|
937 |
for (int j = 0; j != limit; ++j) {
|
kpeter@809
|
938 |
if (!_forward[j]) _res_cap[j] += _lower[j];
|
kpeter@809
|
939 |
}
|
kpeter@809
|
940 |
}
|
kpeter@808
|
941 |
}
|
alpar@877
|
942 |
|
kpeter@839
|
943 |
// Initialize a cost scaling phase
|
kpeter@839
|
944 |
void initPhase() {
|
kpeter@839
|
945 |
// Saturate arcs not satisfying the optimality condition
|
kpeter@839
|
946 |
for (int u = 0; u != _res_node_num; ++u) {
|
kpeter@839
|
947 |
int last_out = _first_out[u+1];
|
kpeter@839
|
948 |
LargeCost pi_u = _pi[u];
|
kpeter@839
|
949 |
for (int a = _first_out[u]; a != last_out; ++a) {
|
kpeter@839
|
950 |
int v = _target[a];
|
kpeter@839
|
951 |
if (_res_cap[a] > 0 && _cost[a] + pi_u - _pi[v] < 0) {
|
kpeter@839
|
952 |
Value delta = _res_cap[a];
|
kpeter@839
|
953 |
_excess[u] -= delta;
|
kpeter@839
|
954 |
_excess[v] += delta;
|
kpeter@839
|
955 |
_res_cap[a] = 0;
|
kpeter@839
|
956 |
_res_cap[_reverse[a]] += delta;
|
kpeter@839
|
957 |
}
|
kpeter@839
|
958 |
}
|
kpeter@839
|
959 |
}
|
alpar@877
|
960 |
|
kpeter@839
|
961 |
// Find active nodes (i.e. nodes with positive excess)
|
kpeter@839
|
962 |
for (int u = 0; u != _res_node_num; ++u) {
|
kpeter@839
|
963 |
if (_excess[u] > 0) _active_nodes.push_back(u);
|
kpeter@839
|
964 |
}
|
kpeter@839
|
965 |
|
kpeter@839
|
966 |
// Initialize the next arcs
|
kpeter@839
|
967 |
for (int u = 0; u != _res_node_num; ++u) {
|
kpeter@839
|
968 |
_next_out[u] = _first_out[u];
|
kpeter@839
|
969 |
}
|
kpeter@839
|
970 |
}
|
alpar@877
|
971 |
|
kpeter@839
|
972 |
// Early termination heuristic
|
kpeter@839
|
973 |
bool earlyTermination() {
|
kpeter@839
|
974 |
const double EARLY_TERM_FACTOR = 3.0;
|
kpeter@839
|
975 |
|
kpeter@839
|
976 |
// Build a static residual graph
|
kpeter@839
|
977 |
_arc_vec.clear();
|
kpeter@839
|
978 |
_cost_vec.clear();
|
kpeter@839
|
979 |
for (int j = 0; j != _res_arc_num; ++j) {
|
kpeter@839
|
980 |
if (_res_cap[j] > 0) {
|
kpeter@839
|
981 |
_arc_vec.push_back(IntPair(_source[j], _target[j]));
|
kpeter@839
|
982 |
_cost_vec.push_back(_cost[j] + 1);
|
kpeter@839
|
983 |
}
|
kpeter@839
|
984 |
}
|
kpeter@839
|
985 |
_sgr.build(_res_node_num, _arc_vec.begin(), _arc_vec.end());
|
kpeter@839
|
986 |
|
kpeter@839
|
987 |
// Run Bellman-Ford algorithm to check if the current flow is optimal
|
kpeter@839
|
988 |
BellmanFord<StaticDigraph, LargeCostArcMap> bf(_sgr, _cost_map);
|
kpeter@839
|
989 |
bf.init(0);
|
kpeter@839
|
990 |
bool done = false;
|
kpeter@839
|
991 |
int K = int(EARLY_TERM_FACTOR * std::sqrt(double(_res_node_num)));
|
kpeter@839
|
992 |
for (int i = 0; i < K && !done; ++i) {
|
kpeter@839
|
993 |
done = bf.processNextWeakRound();
|
kpeter@839
|
994 |
}
|
kpeter@839
|
995 |
return done;
|
kpeter@839
|
996 |
}
|
kpeter@839
|
997 |
|
kpeter@839
|
998 |
// Global potential update heuristic
|
kpeter@839
|
999 |
void globalUpdate() {
|
kpeter@839
|
1000 |
int bucket_end = _root + 1;
|
alpar@877
|
1001 |
|
kpeter@839
|
1002 |
// Initialize buckets
|
kpeter@839
|
1003 |
for (int r = 0; r != _max_rank; ++r) {
|
kpeter@839
|
1004 |
_buckets[r] = bucket_end;
|
kpeter@839
|
1005 |
}
|
kpeter@839
|
1006 |
Value total_excess = 0;
|
kpeter@839
|
1007 |
for (int i = 0; i != _res_node_num; ++i) {
|
kpeter@839
|
1008 |
if (_excess[i] < 0) {
|
kpeter@839
|
1009 |
_rank[i] = 0;
|
kpeter@839
|
1010 |
_bucket_next[i] = _buckets[0];
|
kpeter@839
|
1011 |
_bucket_prev[_buckets[0]] = i;
|
kpeter@839
|
1012 |
_buckets[0] = i;
|
kpeter@839
|
1013 |
} else {
|
kpeter@839
|
1014 |
total_excess += _excess[i];
|
kpeter@839
|
1015 |
_rank[i] = _max_rank;
|
kpeter@839
|
1016 |
}
|
kpeter@839
|
1017 |
}
|
kpeter@839
|
1018 |
if (total_excess == 0) return;
|
kpeter@839
|
1019 |
|
kpeter@839
|
1020 |
// Search the buckets
|
kpeter@839
|
1021 |
int r = 0;
|
kpeter@839
|
1022 |
for ( ; r != _max_rank; ++r) {
|
kpeter@839
|
1023 |
while (_buckets[r] != bucket_end) {
|
kpeter@839
|
1024 |
// Remove the first node from the current bucket
|
kpeter@839
|
1025 |
int u = _buckets[r];
|
kpeter@839
|
1026 |
_buckets[r] = _bucket_next[u];
|
alpar@877
|
1027 |
|
kpeter@839
|
1028 |
// Search the incomming arcs of u
|
kpeter@839
|
1029 |
LargeCost pi_u = _pi[u];
|
kpeter@839
|
1030 |
int last_out = _first_out[u+1];
|
kpeter@839
|
1031 |
for (int a = _first_out[u]; a != last_out; ++a) {
|
kpeter@839
|
1032 |
int ra = _reverse[a];
|
kpeter@839
|
1033 |
if (_res_cap[ra] > 0) {
|
kpeter@839
|
1034 |
int v = _source[ra];
|
kpeter@839
|
1035 |
int old_rank_v = _rank[v];
|
kpeter@839
|
1036 |
if (r < old_rank_v) {
|
kpeter@839
|
1037 |
// Compute the new rank of v
|
kpeter@839
|
1038 |
LargeCost nrc = (_cost[ra] + _pi[v] - pi_u) / _epsilon;
|
kpeter@839
|
1039 |
int new_rank_v = old_rank_v;
|
kpeter@839
|
1040 |
if (nrc < LargeCost(_max_rank))
|
kpeter@839
|
1041 |
new_rank_v = r + 1 + int(nrc);
|
alpar@877
|
1042 |
|
kpeter@839
|
1043 |
// Change the rank of v
|
kpeter@839
|
1044 |
if (new_rank_v < old_rank_v) {
|
kpeter@839
|
1045 |
_rank[v] = new_rank_v;
|
kpeter@839
|
1046 |
_next_out[v] = _first_out[v];
|
alpar@877
|
1047 |
|
kpeter@839
|
1048 |
// Remove v from its old bucket
|
kpeter@839
|
1049 |
if (old_rank_v < _max_rank) {
|
kpeter@839
|
1050 |
if (_buckets[old_rank_v] == v) {
|
kpeter@839
|
1051 |
_buckets[old_rank_v] = _bucket_next[v];
|
kpeter@839
|
1052 |
} else {
|
kpeter@839
|
1053 |
_bucket_next[_bucket_prev[v]] = _bucket_next[v];
|
kpeter@839
|
1054 |
_bucket_prev[_bucket_next[v]] = _bucket_prev[v];
|
kpeter@839
|
1055 |
}
|
kpeter@839
|
1056 |
}
|
alpar@877
|
1057 |
|
kpeter@839
|
1058 |
// Insert v to its new bucket
|
kpeter@839
|
1059 |
_bucket_next[v] = _buckets[new_rank_v];
|
kpeter@839
|
1060 |
_bucket_prev[_buckets[new_rank_v]] = v;
|
kpeter@839
|
1061 |
_buckets[new_rank_v] = v;
|
kpeter@839
|
1062 |
}
|
kpeter@839
|
1063 |
}
|
kpeter@839
|
1064 |
}
|
kpeter@839
|
1065 |
}
|
kpeter@839
|
1066 |
|
kpeter@839
|
1067 |
// Finish search if there are no more active nodes
|
kpeter@839
|
1068 |
if (_excess[u] > 0) {
|
kpeter@839
|
1069 |
total_excess -= _excess[u];
|
kpeter@839
|
1070 |
if (total_excess <= 0) break;
|
kpeter@839
|
1071 |
}
|
kpeter@839
|
1072 |
}
|
kpeter@839
|
1073 |
if (total_excess <= 0) break;
|
kpeter@839
|
1074 |
}
|
alpar@877
|
1075 |
|
kpeter@839
|
1076 |
// Relabel nodes
|
kpeter@839
|
1077 |
for (int u = 0; u != _res_node_num; ++u) {
|
kpeter@839
|
1078 |
int k = std::min(_rank[u], r);
|
kpeter@839
|
1079 |
if (k > 0) {
|
kpeter@839
|
1080 |
_pi[u] -= _epsilon * k;
|
kpeter@839
|
1081 |
_next_out[u] = _first_out[u];
|
kpeter@839
|
1082 |
}
|
kpeter@839
|
1083 |
}
|
kpeter@839
|
1084 |
}
|
kpeter@808
|
1085 |
|
kpeter@810
|
1086 |
/// Execute the algorithm performing augment and relabel operations
|
kpeter@909
|
1087 |
void startAugment(int max_length) {
|
kpeter@808
|
1088 |
// Paramters for heuristics
|
kpeter@839
|
1089 |
const int EARLY_TERM_EPSILON_LIMIT = 1000;
|
kpeter@839
|
1090 |
const double GLOBAL_UPDATE_FACTOR = 3.0;
|
kpeter@808
|
1091 |
|
kpeter@839
|
1092 |
const int global_update_freq = int(GLOBAL_UPDATE_FACTOR *
|
kpeter@839
|
1093 |
(_res_node_num + _sup_node_num * _sup_node_num));
|
kpeter@839
|
1094 |
int next_update_limit = global_update_freq;
|
alpar@877
|
1095 |
|
kpeter@839
|
1096 |
int relabel_cnt = 0;
|
alpar@877
|
1097 |
|
kpeter@809
|
1098 |
// Perform cost scaling phases
|
kpeter@839
|
1099 |
std::vector<int> path;
|
kpeter@808
|
1100 |
for ( ; _epsilon >= 1; _epsilon = _epsilon < _alpha && _epsilon > 1 ?
|
kpeter@808
|
1101 |
1 : _epsilon / _alpha )
|
kpeter@808
|
1102 |
{
|
kpeter@839
|
1103 |
// Early termination heuristic
|
kpeter@839
|
1104 |
if (_epsilon <= EARLY_TERM_EPSILON_LIMIT) {
|
kpeter@839
|
1105 |
if (earlyTermination()) break;
|
kpeter@808
|
1106 |
}
|
alpar@877
|
1107 |
|
kpeter@839
|
1108 |
// Initialize current phase
|
kpeter@839
|
1109 |
initPhase();
|
alpar@877
|
1110 |
|
kpeter@808
|
1111 |
// Perform partial augment and relabel operations
|
kpeter@809
|
1112 |
while (true) {
|
kpeter@808
|
1113 |
// Select an active node (FIFO selection)
|
kpeter@809
|
1114 |
while (_active_nodes.size() > 0 &&
|
kpeter@809
|
1115 |
_excess[_active_nodes.front()] <= 0) {
|
kpeter@809
|
1116 |
_active_nodes.pop_front();
|
kpeter@808
|
1117 |
}
|
kpeter@809
|
1118 |
if (_active_nodes.size() == 0) break;
|
kpeter@809
|
1119 |
int start = _active_nodes.front();
|
kpeter@808
|
1120 |
|
kpeter@808
|
1121 |
// Find an augmenting path from the start node
|
kpeter@839
|
1122 |
path.clear();
|
kpeter@809
|
1123 |
int tip = start;
|
kpeter@839
|
1124 |
while (_excess[tip] >= 0 && int(path.size()) < max_length) {
|
kpeter@809
|
1125 |
int u;
|
kpeter@839
|
1126 |
LargeCost min_red_cost, rc, pi_tip = _pi[tip];
|
kpeter@839
|
1127 |
int last_out = _first_out[tip+1];
|
kpeter@809
|
1128 |
for (int a = _next_out[tip]; a != last_out; ++a) {
|
kpeter@839
|
1129 |
u = _target[a];
|
kpeter@839
|
1130 |
if (_res_cap[a] > 0 && _cost[a] + pi_tip - _pi[u] < 0) {
|
kpeter@839
|
1131 |
path.push_back(a);
|
kpeter@809
|
1132 |
_next_out[tip] = a;
|
kpeter@808
|
1133 |
tip = u;
|
kpeter@808
|
1134 |
goto next_step;
|
kpeter@808
|
1135 |
}
|
kpeter@808
|
1136 |
}
|
kpeter@808
|
1137 |
|
kpeter@808
|
1138 |
// Relabel tip node
|
kpeter@839
|
1139 |
min_red_cost = std::numeric_limits<LargeCost>::max();
|
kpeter@839
|
1140 |
if (tip != start) {
|
kpeter@839
|
1141 |
int ra = _reverse[path.back()];
|
kpeter@839
|
1142 |
min_red_cost = _cost[ra] + pi_tip - _pi[_target[ra]];
|
kpeter@839
|
1143 |
}
|
kpeter@809
|
1144 |
for (int a = _first_out[tip]; a != last_out; ++a) {
|
kpeter@839
|
1145 |
rc = _cost[a] + pi_tip - _pi[_target[a]];
|
kpeter@809
|
1146 |
if (_res_cap[a] > 0 && rc < min_red_cost) {
|
kpeter@809
|
1147 |
min_red_cost = rc;
|
kpeter@809
|
1148 |
}
|
kpeter@808
|
1149 |
}
|
kpeter@809
|
1150 |
_pi[tip] -= min_red_cost + _epsilon;
|
kpeter@809
|
1151 |
_next_out[tip] = _first_out[tip];
|
kpeter@839
|
1152 |
++relabel_cnt;
|
kpeter@808
|
1153 |
|
kpeter@808
|
1154 |
// Step back
|
kpeter@808
|
1155 |
if (tip != start) {
|
kpeter@839
|
1156 |
tip = _source[path.back()];
|
kpeter@839
|
1157 |
path.pop_back();
|
kpeter@808
|
1158 |
}
|
kpeter@808
|
1159 |
|
kpeter@809
|
1160 |
next_step: ;
|
kpeter@808
|
1161 |
}
|
kpeter@808
|
1162 |
|
kpeter@808
|
1163 |
// Augment along the found path (as much flow as possible)
|
kpeter@809
|
1164 |
Value delta;
|
kpeter@839
|
1165 |
int pa, u, v = start;
|
kpeter@839
|
1166 |
for (int i = 0; i != int(path.size()); ++i) {
|
kpeter@839
|
1167 |
pa = path[i];
|
kpeter@809
|
1168 |
u = v;
|
kpeter@839
|
1169 |
v = _target[pa];
|
kpeter@809
|
1170 |
delta = std::min(_res_cap[pa], _excess[u]);
|
kpeter@809
|
1171 |
_res_cap[pa] -= delta;
|
kpeter@809
|
1172 |
_res_cap[_reverse[pa]] += delta;
|
kpeter@809
|
1173 |
_excess[u] -= delta;
|
kpeter@809
|
1174 |
_excess[v] += delta;
|
kpeter@809
|
1175 |
if (_excess[v] > 0 && _excess[v] <= delta)
|
kpeter@809
|
1176 |
_active_nodes.push_back(v);
|
kpeter@808
|
1177 |
}
|
kpeter@839
|
1178 |
|
kpeter@839
|
1179 |
// Global update heuristic
|
kpeter@839
|
1180 |
if (relabel_cnt >= next_update_limit) {
|
kpeter@839
|
1181 |
globalUpdate();
|
kpeter@839
|
1182 |
next_update_limit += global_update_freq;
|
kpeter@839
|
1183 |
}
|
kpeter@808
|
1184 |
}
|
kpeter@808
|
1185 |
}
|
kpeter@808
|
1186 |
}
|
kpeter@808
|
1187 |
|
kpeter@809
|
1188 |
/// Execute the algorithm performing push and relabel operations
|
kpeter@810
|
1189 |
void startPush() {
|
kpeter@808
|
1190 |
// Paramters for heuristics
|
kpeter@839
|
1191 |
const int EARLY_TERM_EPSILON_LIMIT = 1000;
|
kpeter@839
|
1192 |
const double GLOBAL_UPDATE_FACTOR = 2.0;
|
kpeter@808
|
1193 |
|
kpeter@839
|
1194 |
const int global_update_freq = int(GLOBAL_UPDATE_FACTOR *
|
kpeter@839
|
1195 |
(_res_node_num + _sup_node_num * _sup_node_num));
|
kpeter@839
|
1196 |
int next_update_limit = global_update_freq;
|
kpeter@839
|
1197 |
|
kpeter@839
|
1198 |
int relabel_cnt = 0;
|
alpar@877
|
1199 |
|
kpeter@809
|
1200 |
// Perform cost scaling phases
|
kpeter@809
|
1201 |
BoolVector hyper(_res_node_num, false);
|
kpeter@839
|
1202 |
LargeCostVector hyper_cost(_res_node_num);
|
kpeter@808
|
1203 |
for ( ; _epsilon >= 1; _epsilon = _epsilon < _alpha && _epsilon > 1 ?
|
kpeter@808
|
1204 |
1 : _epsilon / _alpha )
|
kpeter@808
|
1205 |
{
|
kpeter@839
|
1206 |
// Early termination heuristic
|
kpeter@839
|
1207 |
if (_epsilon <= EARLY_TERM_EPSILON_LIMIT) {
|
kpeter@839
|
1208 |
if (earlyTermination()) break;
|
kpeter@808
|
1209 |
}
|
alpar@877
|
1210 |
|
kpeter@839
|
1211 |
// Initialize current phase
|
kpeter@839
|
1212 |
initPhase();
|
kpeter@808
|
1213 |
|
kpeter@808
|
1214 |
// Perform push and relabel operations
|
kpeter@809
|
1215 |
while (_active_nodes.size() > 0) {
|
kpeter@839
|
1216 |
LargeCost min_red_cost, rc, pi_n;
|
kpeter@809
|
1217 |
Value delta;
|
kpeter@809
|
1218 |
int n, t, a, last_out = _res_arc_num;
|
kpeter@809
|
1219 |
|
kpeter@839
|
1220 |
next_node:
|
kpeter@808
|
1221 |
// Select an active node (FIFO selection)
|
kpeter@809
|
1222 |
n = _active_nodes.front();
|
kpeter@839
|
1223 |
last_out = _first_out[n+1];
|
kpeter@839
|
1224 |
pi_n = _pi[n];
|
alpar@877
|
1225 |
|
kpeter@808
|
1226 |
// Perform push operations if there are admissible arcs
|
kpeter@809
|
1227 |
if (_excess[n] > 0) {
|
kpeter@809
|
1228 |
for (a = _next_out[n]; a != last_out; ++a) {
|
kpeter@809
|
1229 |
if (_res_cap[a] > 0 &&
|
kpeter@839
|
1230 |
_cost[a] + pi_n - _pi[_target[a]] < 0) {
|
kpeter@809
|
1231 |
delta = std::min(_res_cap[a], _excess[n]);
|
kpeter@809
|
1232 |
t = _target[a];
|
kpeter@808
|
1233 |
|
kpeter@808
|
1234 |
// Push-look-ahead heuristic
|
kpeter@809
|
1235 |
Value ahead = -_excess[t];
|
kpeter@839
|
1236 |
int last_out_t = _first_out[t+1];
|
kpeter@839
|
1237 |
LargeCost pi_t = _pi[t];
|
kpeter@809
|
1238 |
for (int ta = _next_out[t]; ta != last_out_t; ++ta) {
|
alpar@877
|
1239 |
if (_res_cap[ta] > 0 &&
|
kpeter@839
|
1240 |
_cost[ta] + pi_t - _pi[_target[ta]] < 0)
|
kpeter@809
|
1241 |
ahead += _res_cap[ta];
|
kpeter@809
|
1242 |
if (ahead >= delta) break;
|
kpeter@808
|
1243 |
}
|
kpeter@808
|
1244 |
if (ahead < 0) ahead = 0;
|
kpeter@808
|
1245 |
|
kpeter@808
|
1246 |
// Push flow along the arc
|
kpeter@839
|
1247 |
if (ahead < delta && !hyper[t]) {
|
kpeter@809
|
1248 |
_res_cap[a] -= ahead;
|
kpeter@809
|
1249 |
_res_cap[_reverse[a]] += ahead;
|
kpeter@808
|
1250 |
_excess[n] -= ahead;
|
kpeter@808
|
1251 |
_excess[t] += ahead;
|
kpeter@809
|
1252 |
_active_nodes.push_front(t);
|
kpeter@808
|
1253 |
hyper[t] = true;
|
kpeter@839
|
1254 |
hyper_cost[t] = _cost[a] + pi_n - pi_t;
|
kpeter@809
|
1255 |
_next_out[n] = a;
|
kpeter@809
|
1256 |
goto next_node;
|
kpeter@808
|
1257 |
} else {
|
kpeter@809
|
1258 |
_res_cap[a] -= delta;
|
kpeter@809
|
1259 |
_res_cap[_reverse[a]] += delta;
|
kpeter@808
|
1260 |
_excess[n] -= delta;
|
kpeter@808
|
1261 |
_excess[t] += delta;
|
kpeter@808
|
1262 |
if (_excess[t] > 0 && _excess[t] <= delta)
|
kpeter@809
|
1263 |
_active_nodes.push_back(t);
|
kpeter@808
|
1264 |
}
|
kpeter@808
|
1265 |
|
kpeter@809
|
1266 |
if (_excess[n] == 0) {
|
kpeter@809
|
1267 |
_next_out[n] = a;
|
kpeter@809
|
1268 |
goto remove_nodes;
|
kpeter@809
|
1269 |
}
|
kpeter@808
|
1270 |
}
|
kpeter@808
|
1271 |
}
|
kpeter@809
|
1272 |
_next_out[n] = a;
|
kpeter@808
|
1273 |
}
|
kpeter@808
|
1274 |
|
kpeter@808
|
1275 |
// Relabel the node if it is still active (or hyper)
|
kpeter@809
|
1276 |
if (_excess[n] > 0 || hyper[n]) {
|
kpeter@839
|
1277 |
min_red_cost = hyper[n] ? -hyper_cost[n] :
|
kpeter@839
|
1278 |
std::numeric_limits<LargeCost>::max();
|
kpeter@809
|
1279 |
for (int a = _first_out[n]; a != last_out; ++a) {
|
kpeter@839
|
1280 |
rc = _cost[a] + pi_n - _pi[_target[a]];
|
kpeter@809
|
1281 |
if (_res_cap[a] > 0 && rc < min_red_cost) {
|
kpeter@809
|
1282 |
min_red_cost = rc;
|
kpeter@809
|
1283 |
}
|
kpeter@808
|
1284 |
}
|
kpeter@809
|
1285 |
_pi[n] -= min_red_cost + _epsilon;
|
kpeter@839
|
1286 |
_next_out[n] = _first_out[n];
|
kpeter@808
|
1287 |
hyper[n] = false;
|
kpeter@839
|
1288 |
++relabel_cnt;
|
kpeter@808
|
1289 |
}
|
alpar@877
|
1290 |
|
kpeter@808
|
1291 |
// Remove nodes that are not active nor hyper
|
kpeter@809
|
1292 |
remove_nodes:
|
kpeter@809
|
1293 |
while ( _active_nodes.size() > 0 &&
|
kpeter@809
|
1294 |
_excess[_active_nodes.front()] <= 0 &&
|
kpeter@809
|
1295 |
!hyper[_active_nodes.front()] ) {
|
kpeter@809
|
1296 |
_active_nodes.pop_front();
|
kpeter@808
|
1297 |
}
|
alpar@877
|
1298 |
|
kpeter@839
|
1299 |
// Global update heuristic
|
kpeter@839
|
1300 |
if (relabel_cnt >= next_update_limit) {
|
kpeter@839
|
1301 |
globalUpdate();
|
kpeter@839
|
1302 |
for (int u = 0; u != _res_node_num; ++u)
|
kpeter@839
|
1303 |
hyper[u] = false;
|
kpeter@839
|
1304 |
next_update_limit += global_update_freq;
|
kpeter@839
|
1305 |
}
|
kpeter@808
|
1306 |
}
|
kpeter@808
|
1307 |
}
|
kpeter@808
|
1308 |
}
|
kpeter@808
|
1309 |
|
kpeter@808
|
1310 |
}; //class CostScaling
|
kpeter@808
|
1311 |
|
kpeter@808
|
1312 |
///@}
|
kpeter@808
|
1313 |
|
kpeter@808
|
1314 |
} //namespace lemon
|
kpeter@808
|
1315 |
|
kpeter@808
|
1316 |
#endif //LEMON_COST_SCALING_H
|